Process for production of 1, 4 saturated diols



United States PatentO ice Pawn, 522 1 ,1 3

1 2 2 992 278 alytic hydrogenation of the corresponding tertiary acetlenic 1,4-diols without a 1 eciable h dro enol sis side PROCESS FOR lRdDUCTION F 1,4 Ze ppr y g y SATURATED DIOLS It has been found that the above objects may be ifi hafiififiici filffiifiif iifiaiie i iif tywmvletelvhydmgmmgawrfimmyleec NY. a dorporafion of New York' 1,4-d1ol 1n the presence of a catalyst system comprising No Drawing. Filed Dec. 12, 1957, SeruNo. 102,255 a metal catalyst selected from the group wnslstmg of Cl i ((31, 260-617) palladium, platinum and rhodium and a small amount of an alkaline material such, for example, as NaOH, KOH This invention relates to a novel process for the manll- 10 or triethylamine. Advantageously, by the use of a small facture of saturated 1,4-diols in high yields and high amount of such alkaline material in conjunction with purity. More particularly, it concerns a process for prothe aforementioned hydrogenation catalysts, hydrogenducing tertiary saturated 1,4-diols by the complete catolysis side reactions are substantially completely supalytic hydrogenation of the corresponding tertiary acetpressed. By the present process extremely high yields ylenic 1,4-diols. of the saturated 1,4-diols are obtained through the hy- Heretofore, the processes used for hydrogenating terdrogenation of acetylenic 1,4-d1'ols without undesirable tiary acetylenic 1,4-diols have not resulted in the producformation of other products. tion of tertiary saturated 1,4-diols in high yields and of -In general, the present process involves dissolving the high purity. In many instances the catalyst system emalkaline material in the acetylenic 1,4-diols at a suitable ployed resulted in an incomplete hydrogenation wheretemperature, said diol being either dissolved in a suitable 'by. the triple bond was partially saturated with the formainert solvent or in molten form. The palladium or platition of a double bond which was not further reduced num catalyst is then added and the hydrogenation carried resulting in the formation of an olefinic diol. Such a out at a moderate temperature and pressure. The hysystem is the nickel-alkaline material catalyst system disdrogenation is carried out until there is no longer a closed in Vaughn US. Patent 2,157,365. On the other drop inpressure indicating that the reaction is complete. hand, other catalyst systems, such, for example, as plati- The present invention is applicable generally to the num and palladium catalysts disclosed in the above re f! om lete hydrogenation or the class of acetylenic 1,4-

ferred to Vaughn patent, eflect complete hydrogenation di 1s of the type but do not prevent the occurrence of hydrogenolysis side 0H 0H reactions. When such side reactions occur there is pro duced a substantial amount of undesirable side reaction products and a low amount of the desired tertiary satu- 3 rated 1,4-diol. wherein R, R R and R respectively designate either When a catalyst is employed which serves to eflzect hydrogen, the Same a difieffent y cycloalkyl or complete hydrogenation, the hydrogenation and hydroryl g P- Examples of Such diols are:

genolysis of tertiary acetylenic 1,4-diols may be shown 2,5 dimethyl 3 hexryne 2,5 diol, 3,6 dimethylto proceed by the following route: 4 octyne 3,6 diol, 2,4,7,9 tetramethyl 5 decyne- R1 R1 R1 R1 R1 R1 I l H: l 1 Br- C:C-C-R| RzCCH=CH-CRn Rr-C-CHPCHz- -Rg H H H H H H H2 lH2O R1 R1 R1 R1 R1 I Hi l a l l t Ra(J-CH=OH?Rg H0 Rz--[-CH=CH- R| RzI-CH2CHz ---R:

H H 2 H H H H 111! I H -1 Rr(IJ-CHzCHa(lJ-R H H It is seen from the above route that complete catalytic l 4,7 diol, 4,7 'dimethyl 5 decyne 4,7 diol, 2,5 dihydrogenation of tertiary acetylenic 1,4-diols is in genphenyl 3 hexyne 2,5 diol and his (cyclohexyl) eral an unselective process resulting in low yields of the acetylene glycol.

desired saturated 1,4-diol due to hydrogenolysis side re Any solvent which will dissolve the tertiary acetylenic actions. For example, the complete hydrogenation of diol and which does not react with it may be used. This 2,5-dimethyl-3-hexyn-2,5-diol (1) yields a mixture of 2,5- will vary depending upon the particular material used.-

dimethyl hexane (7), 2,5-dimethyl-hexane-2-ol (4), 2,5- Since the alkaline material used in accordance with this dimethy1-3-hexene-2-ol (5), and the desired 2,5-dime'thyl, invention is readily soluble in molten, low melting (35- hexane-2,5-diol (3). The 1,4-saturated diol is generally 55 C.) acetylenic diols due to alcoholate or complex isolated in 10-32% yield on complete hydrogenation. formation, the solvent is not needed to effect solution of Accordingly, it is the object of this invention to provide the base. In fact, KOH and NaOH which are completely a novel process for the production of tertiary saturated insoluble in non-polar solvents such as petroleum ether,

1,4-diols in high yields and of high purity. More partichexane, heptane, toluene, etc., dissolve in a solution of:

ularly, it is an object of this invention to provide a novel the acetylenic diol in any of these solvents. The base process for the production of tertiary saturated 1,4-diols,

employed should be soluble in the diol-solvent mixture in high yields and of high purity, by the complete catand not merely dispersed in it since this inhibit its adsorption (chemisorption) upon the catalyst surface.

Heptane has been found to be an excellent solvent for dimethyl octynediol, dimethyl decynediol and tetramethyl decynediol. Toluene is the preferred solvent for dimethyl hexynediol, while the preferred solvents for diphenyl hexynediol and bis-cyclohexyl glycol are methanoland isopropanol.

Complete hydrogenation in accordance with the present invention is carried out under moderate pressure and temperature. In general, the pressure is in a range from 30 to 500 p.s.i.g. and preferably 30 to 50 p.s.i.g.; and, the temperature is in general in the range of 55 to 125 C. and preferably in the range of 55 to 85 C. When the temperature is significantly below the indicated minimum temperature the hydrogenation rate is too slow; While when it is much above the indicated maximum temperature, the base catalyzed decomposition of the acetylenic diol into a mixture of ethynyl carbinol, ketone and free acetylene takes place. After the reaction mixture has been heated to a suitable temperature to initiate the reaction, no additional heat is necessary in the first stage of hydrogenation for the reaction is exothermic. However, heat is applied subsequently to effectuate complete hydrogenation.

As indicated hereinabove, the presence of a small amount of alkaline material in conjunction with a palladium, rhodium or platinum catalyst effects complete hydrogenato-n of the tertiary acetylenic 1,4-diol so as to produce the corresponding tertiary saturated 1,4-diol in high yields and of high purity. Any alkaline reacting agent may be used for this purpose, such, for example, as an alkali metal hydroxide or a basic organic amine which can react with the acetylenic diol to form either an alcoholate (alkoxide) or complex in which hydrogen bonding may be involved. Examples of additional alkaline materials which may be used are alkali metal hydroxides such, for example, as lithium hydroxide,'cesium hydroxide and rubidium hydroxide; and, tertiary amines such, for example, as pyridine and tripropylamine. By. employing such a catalyst system the process is selective resulting in the production of the desired tertiary saturated 1,4-diol without appreciable hydrogenolysis side reactions. The catalyst may be in any amount normally used for hydrogenation reactions. When the catalyst is a supported catalyst containing metal catalyst such, for example, as palladium on charcoal, excellent results have been obtained when the supported catalyst (carrier plus metal catalyst) is in an amount from 0.25 to 1.0 g. (.0125 to .05 g. metal catalyst) per mole of tertiary acetylenic 1,4-diol. Of course the amount of catalyst employed affects the amount of alkaline material or base that should be employed. For example, 1.0 g. of Pd on charcoal (5% Pd) catalyst generally requires 0.025-0.05 g. of alkaline material, while 0.25 g. of the same catalyst generally requires 0.0063 to 0.0125 g. of base. Preferably, it is preferred to employ a catalyst supported on an inert catalyst, such, for example, as platinum on charcoal, rhodium on charcoal, or palladium on charcoal. Neutral charcoal is the preferred carrier for it is inert and does not interfere with complete hydrogenation. Any other carrierv which does not prevent complete hydrogenation may beused, however, such, for example, as CaCO BaOO BaSO and neutral clays.

Carriers which tend to limit the hydrogenation to semihydrogenation should be avoided. Acidic carriers should be avoided since they tend to cause dehydration of acetylenic diols to ene-yn-ol structures. Hence, carriers containing acidic mixtures H 80 'HCl, H PO acetic acid, boric acid, acid sulfates, acidic phosphates must be avoided as well as acid washed charcoal. Also,

carriers containing sulfur or metallic carbinols or heavy metal impurities may be poisonous to the catalyst. The catalyst is preferably supported since the hydrogenation art. and practical considerations make this advisable. 1f

' ic glycol.

so desired, however, the carrier may be eliminated and the catalyst suspended in the reaction mixture before hydrogenation.

The alkaline material should be present in an amount sufficient to prevent hydrogenolysis side reactions and yet permit complete hydrogenation. The amount of alkaline material required will vary depending upon the alkaline material that is employed and the particular acetylenic diol that is to be completely hydrogenated. Also, as pointed out hereinbefore, the amount of catalyst employed will affect the amount of base required. In general, the alkaline material is in a range of 0.01 to 0.3 g. and preferably .05 to 0.2 g. per mole of acetylen- For acetylenic diols such, for example, as dimethyloctyndiol, diphenyl hexyndiol, 4,7-dimethyl-5 decyne 4,7 diol and 2,4,7,9 tetramethyl 5 decyne- 4,7-diol, a range of 0.025 to 0.05 g. is generally employed with 0.05 g. being preferred. For acetylenic diols exemplified by dimethyl hexyndiol lower amounts are generally used in the range of 0.015 g. to 0.025 g. with 0.025 g. being preferred. If the alkaline material is in an amount well below the above indicated ranges inadequate hydrogenolysis inhibition is obtained while if the alkaline material is in an amount well above the indicated range incomplete hydrogenation results.

The following general procedure may be used for producing tertiary saturated 1,4-diols from corresponding tertiary acetylenic 1,4-diols in accordance with the present invention:

\ n-heptane when dimethyl octynediol is the react-ant diol or 'isopropanol when a less soluble diphenyl hexynediol is the diol. The diol is heated to solution at a suitable temperature such, for example, as 6065 C. and is quickly treated with 0.025 g. of a suitable alkaline material such,ffor example, as powdered KOH and stirred at 60-65 C. for 2-5 minutes until the KOH has completely dissolved.

One gram of palladium on charcoal catalyst (5% Pd) is then added to the solution at 60-65 C. and then the hydrogenation begun without delay. The hydrogenation temperature and pressure employed is 60-65" C. and 30-55 p.s.i.g. The reaction during this stage of the reaction is exothermic and requires frequent air or water cooling to maintain the desired temperature range. When the reaction proceeds to a point where it is no longer exothermic, external :heating is applied to raise the temperature to 65-75 C. to complete the hydrogenation. Hydrogenation to the saturated diol is continued until there is no further pressure drop after 30 minutes.

The reaction mixture is filtered to separate the catalyst, diluted with cc. heptane (including washing of funnel and transfer rinses) and transferred to a typical waterimmiscible solvent azeotrope separator (Dean Stark tube) The heptane layer is heated under vigorous reflux and any water of hydrogenolysis collected and measured. Hydrogenations protected with KOH yield insignificant amounts (less than 0.20 g.) of water while unprotected hydrogenations yield 6-10 g. water per 0.50 mole run.

Heptane is flash distilled from the desired diol at atmospheric pressure to a pot temperature of C. followed by gradually diminished pressure. The saturated diols are vacuum distilled through a twelve inch vacuum jacketed Vigreux at the following temperatures and pressures:

Saturated diols Temperature 0.) and Pressure 2,5-dlmethylhexane-2,fi-dlol 95 4 mm. (M.P. ass-s9 Bis-cyclohexane-l,Z-ethanediolL -I (M.P.132133)".

Distillation (13 mm.):

(a) 70-85 C 22 g. (hydrocarbon plus dimethyl decanol). (b) 92-93 C 54 g. (57.7% conv.) dimethyl decanol. (c) 100-123125 C 14.5 g. (7.2% conv.)

crude saturated diol.

Following the general procedure outlined above, a number of tertiary acetylenic 1,4-diols were hydrogenated at a temperature in the range of 60-65 C. and a pressure in the range of 30-55 p.s.i.g. employing 1 g. of palladium on charcoal catalyst (5% Pd). The experimental conditions and results of these examples are summarized in Table I.

- Examples II, V, VII, IX, XI, XIII and XV illustrat the process of the present invention wherein the palladium catalyst employed in conjunction with potassium hydroxide in an amount suflicient to inhibit hydrogenolysis but yet permit complete hydrogenation. Examples I, IV, VI,.VIII, X, XII, XIV illustrate prior art processes utilizing the palladium catalyst in the absence of an alkaline material. Example IH shows the poor results obtained when too high an amount of alkaline material is used. Accordingly, this example is outside the scope of the present invention.

From the aforementioned Table II, it will be observed that triethylamine and sodium hydroxide like potassium hydroxide inhibit hydrogenolysis but are not as effective as the preferred alkaline material potassium hydroxide.

Results of hydrogenation of dimethyl decynediol with platinum on charcoal catalyst with potassium hydroxide are summarized in Table III below. The reaction conditions of 30-55 p.s.-i.g. 60-65 C. and heptane as solvent were employed.

Table III Saturated diol Purity Percent Yield XVIII 0. 20 83. 3 99.97

It is observed from the results of Example XVIII and from the results of Example V (Table I) that palladium is a more effective catalyst than platinum when used in accordance with the present invention.

Although the foregoing disclosure is principally concerned with the hydrogenation of tertiary acetylenic 1,4- diols wherein the problem with respect to hydrogenolysis is the most serious, it should be realized that the principles of the present invention are also applicable to the hydrogenation of primary and secondary acetylenic diols.

The invention in its broader aspects is not limited to the specific steps, methods, compositions, combinations and improvements described but departures may be made therefrom within the scope of the accompanying claims Without departing from the principles of the invention and without sacrificing its chief advantages.

I claim: a

.1. An improved process for producing a saturated 1,4-diol in high yield and purity from its corresponding Table I Reaction Pressure Drop Percent Example Tertiary acetylenic 1,4-dlol Diol, KOH Time 1110 (g.)

No. moles base (g.) (min) formed Obsv. Cale. Oonv Purity Tetramethyl deoynedlol g0. m) 0. 0 300 9. 0 101 85 33. 0 o- 0:501:11) 0. 05 300 0.2 85 85 89. 5 99. 9 Dimethyl decynedlol (0. m) 0. 20 840 0. 2 63 85 71. 3 74. 0 do (0. 50m; 0. 0 90 6. 0 122 85 7. 2 do- (0. 50m 0. 05 150 0. 2 85 85 94 99. 6 Dimethyloctyne diol (0. 50m) 0 225 7. 5 109 85 15. 0 0 (0.50m) 0.025 105 0.20 87 85 87.4 99.9 Dlmethyl hexynedlol (0. 50m) 0 10. 2 131 31. 5 o- (0. 50m) 0. 025 180 0. 99 84 85 84. 7 97. 2 Bls-cyclohexyl acetylene glycoL. (0.30m) 0 120 7.4 66 51 8. 9 Crude o- (0. 30m; 0. 05 0. 2O 53 51 94 99. 9 Diphenyl hexynediol 0. 25m 0 77 57 42. 5 35. 6 Crude d0 0. 25m) 0. 05 150 0. 2O 41 42. 6 94. 8 95 (10. 0. 125m) 0 2. 31 27 21. 2 do- 0. m) 0. 015 0. 20 21. 0 21. 3 94 99. 9

The following Examples XVI and XVII summarized in Table II illustrate the process of the present invention employing a palladium on charcoal catalyst but different alkaline materials from the KOH employed in the previous examples, i.e., NaOH and triethylamine. The temperature of the reaction in each instance was 60-70 C. and the pressure in the range of 30-55 p.s.i.-g.

acetylenic 1,4-diol comprising hydrogenating said acetylenic 1,4-diol in the presence of a catalyst selected from the group consisting of palladium, rhodium and platinum and an alkaline material, said alkaline material being present in an amount from about 0.010 to 0.3 g. per mole of teritary acetylenic 1,4-diol, whereby said acet- Table II Reaction Pressure Drop Percent Example Tertiarlairiegylenlc Dlclfl, Base (g.) are) lEtIggnggi) No. 0 mo es Obsv. Cale. Oonv. Purity XVI Tetramethyl deeynedioL. (0.50m) Triethylamine (0.05)-. 90 0.40 85.5 85 90.5 97.5 XVII"--- Dlmethyl deeynediol (0.50m) NaOH (0.05) 200 0.20 83 85 90 99.8

7 ylenic 1,4-diol is converted to its corresponding saturated 1,4-diol.

2. An improved process for producing a tertiary saturated 1,4-diol in high yield and purity from its corresponding tertiary acetylenic 1,4-diol comprising hydrogenating said tertiary acetylenic 1,4-diol in the presence of a catalyst selected from the group consisting of palladium, rhodium and platinum and an alkaline material, said alkaline material being present in an amount from about 0.010 to 0.3 g. per mole of tertiary acetylenic 1,4-diol, whereby said tertiary acetylenic 1,4-diol is converated to its coresponding tertiary saturated 1,4-dio1.

3. An improved process for producing a tertiary saturated 1,4-dil in high yield and purity from its corresponding tertiary acetylenic 1,4-diol comprising completely hydrogenating said tertiary acetylenic 1,4-diol at a temperature in the range of 55 to 85 C. and a pressure in the range of 30 to 55 p.s.i.g. in the presence of a catalyst selected from the group consisting of palladium, rhodium and platinum and an alkaline material, said alkaline material being present in an amount from 0.05 to 0.2 gram per mole of acetylenic 1,4-diol, whereby said tertiary acetylenic 1,4-diol is converted to its corresponding tertiary sat-urated 1,4-di0l.

4. A process according to claim 3 wherein the alkaline material is potassium hydroxide.

5. A process according to claim 3 wherein the alkaline material is a basic organic amine. I

6. A process according to claim 3 wherein the tertiary acetylenic 1,4-diol as selected from the group consisting of 2,5-dimethyl-3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne- 3,6-diol, 2,4,7,9-tetramethy1-5-decyne-4,7-diol, 4,7-dimethyl-5-decyne-4,7-diol, 2,5-diphenyl-3-hexyne-2,5-diol and bis-(cyclohexyl) acetylenic glycol.

7. An improved process for producing a tertiary saturated 1,4-diol in high yield and purity from its corresponding tertiary acetylenic 1,4-diol comprising hydrogenating said tertiary acetylenic 1,4-diol at a temperature in the range of 55 to 125 C. and a pressure inthe range of 30 to 500 p.s.i.g. in the presence of a catalyst selected from the group consisting of palladium, rhodium and platinum and an alkaline material, said alkaline material being present in an amount from about 0.010 to 0.3 g. per mole of tertiary acetylenic 1,4-diol, whereby said tertiary acetylenic 1,4-diol is converted to its corresponding tertiary saturated 1,4-diol.

8. An improved process for producing a tertiarysaturated :1,4.-diol in high yield and purity from itscorresponding tertiary acetylenic 1,4-dio1 comprising hydrogeiiating said tertiary acetylenic 1,4-'diol at a temperature in the range of to C. and a pressure in the range of 30 to 55 pls.i.g. in the presence of a palladium'catalyst and an alkaline material, said alkaline materialbeing present 'in an amount from 0.05 to 0.2 g. per mole of acetylenic 1,4-diol, whereby said tertiary acetylene 1,4- diol is converted to its corresponding tertiary saturated 1,4-diol.

9. An improved process for producing a tertiary saturated 1,4-diol in high yield and purity from its corresponding tertiary acetylenic 1,4-diol comprising hydrogenating said tertiary acetylenic 1,4-diol at a temperature in the range of 55 to 85 C. and a pressure in the range of 30 to 55 p.s.i.g. in the presence of a palladium'catalyst on a non-acidic carrier and an alkaline material, said alkaline material being present in an amount from 0.05 to 0.2 g. per mole of acetylenic 1,4-diol, whereby said tertiary acetylenic 1,4-diol is converted to its corresponding tertiary saturated 1,4-diol.

10. An improved process for producing a tertiary saturated 1,4-diol in high yield and purity from its corresponding tertiary acetylenic 1,4-diol comprising completely hydrogenating a tertiary acetylenic 1,4-diol selected from the group consisting of 2,5-dimethyl-3-hexyne-2,5- diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5- decyne-4,7-diol, 4,7-dimethyl-5-decyne 4,7 diol, 2,5-diphenyl-3-heXyne-2,5-diol and bis-(cyclohexyl) acetylene glycol at a temperature in the range of 55 to 85 C. and a pressure in the range of 30 to 55 p.s.i.g. in the presence of a palladium catalyst and an alkaline material, said alkaline material being present in an amount from 0.05 to 0.2 g. per mole of acetylenic 1,4-diol, whereby said tertiary acetylenic 1,4-diol is converted to its corresponding tertiary saturated 1,4-diol.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Papa et al.: Jour. Amer. Chem. Soc., vol. 76 (1954), pages 4446-50 (5 pages). 

1. AN IMPROVED PROCESS FOR PRODUCING A SATURATED 1,4-DIOL IN HIGH YIELD AND PURITY FROM ITS CORRESPONDING ACEYLENIC 1,4-DIOL COMPRISING HYDROGENATING SAID ACETYLENIC 1,4-DIOL IN THE PRESENCE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF PALLADIUM, RHODIUM AND PLATINUM AND AN ALKALINE MATERIAL, SAID ALKALINE MATERIAL BEING PRESENT IN AN AMOUNT FROM ABOUT 0.010 TO 0.3 G. PER MOLE OF TERITARY ACETYLENIC 1,4-DIOL, WHEREBY SAID ACETYLENIC 184-DIOL IS CONVERTED TO ITS CORRESPONDING SATURATED 1,4-DIOL. 